The extraction and recovery of essential oil from citrus fruit is discussed in the Brazilian patents PI 8002964 and PI 8402231, both no longer valid. Said patents refer to machines previously described in the U.S. Pat. Nos. 3,707,176, 3,954,032 and 4,070,959, which are incorporated herein as general reference.
The Brazilian patent PI 8002964 describes a device to extract oil from the peel of non-round citrus fruit and refers to the non-suitability of the machines as described in the U.S. Pat. Nos. 3,707,176, 3,954,032 and 4,070,959 for such an application. That device comprises a pair of parallel horizontal serrated cylinders forming recesses within them to receive the fruit, means to rotate said cylinders in the same sense and means to cause axial displacement movement relative to said cylinders, so that such axial displacement promotes a change in fruit direction relative to such cylinders. Furthermore, said cylinders are immersed in water.
Oil extraction in that equipment is accomplished by cutting the fruit peel by the cylinders in a region below the water level.
The Brazilian patent PI 8402231 refers directly to U.S. Pat. No. 4,070,959 and presents an improvement therein introduced. As described in the mentioned patent PI 8402231, the improvement consists of providing water spraying pipes, spaced apart inside the closed recipient, intended to spray water directly over the external surface of each fruit, thus carrying the essential oil extracted from them through the cylinder teeth. As per the description, that improvement intends to keep any bacteria coming from so-called “lower quality” fruit from being transferred to good quality fruit through the “water bath”. It is also noted in FIGS. 6 and 7 of that patent that the serrated rings have a slight inclination relative to the cylinder that supports them.
Despite the fact that such machines, as described above, perform acceptable processes of extraction of essential oil from citrus fruit, they present, industrially speaking, a few limitations regarding the art, such as operation conditions, maintenance and versatility of application required by an industrial process. Some of these limitations can be summarized as follows:                equipment modularity—machines known in the art are large, appropriate only for high production and therefore built as individual units, specific to meet a given application;        emulsion tank—there is one single tank with the purpose of a tank per se, with structure to receive the bearing of a disk shaft acting both as a bearing and sealing. Sealing uses an o-ring, which limits the shaft rotation to a lower rotation than the bearing. This does not allow increasing the rotation and processing ability of the machine;        bearing of disk shaft—the bearing is made of graphite chuck, it is self-aligning and has rolling purposes. It has axial translation and sealing to limit rotation, thus forbidding an increase in speed and in fruit processing capacity. Graphite used in the bearing promotes emulsion contamination, as it is in direct contact with said bearing;        axial movement system—operation is done by means of a rotating lateral axis, by intermediate vertical axis actuated by cylindrical cams, operated by means of arms and two axis simultaneously. That configuration requires a larger quantity of items, such as bearings for the lateral axis, vertical axis, fastening supports and further lubricating points;        disk cleaning system—Cleaning is manual, using a high-pressure hose, with the remaining fruit over the disks needing previous removal.        fruit feed system—Fruit are fed in batches, by means of a timer.        